grpc-hello-world-mvn does not build in ubuntu

After downloading repo at https://github.com/GoogleCloudPlatform/kotlin-samples/commit/41339a36aaa1feb6b50789964ba8f5795f53b18e, **grpc-hello-world-mvn** it does not build properly.
There is an error report by **ktlin-maven-plugin**: `object GreeterGrpcKt should be declared in a file named GreeterGrpcKt.kt`

Looking at generated source files, effectively there is no **GreeterGrpcKt.kt** file, instead there is one with same expected information but named **HelloWorldGrpcKt.kt** (see image at the bottom). Due to this, **HelloWorldServer** and **HelloWorldClient** are not able to find required dependencies as well.

Here is the information about my OS
```
[INFO] Detecting the operating system and CPU architecture
[INFO] ------------------------------------------------------------------------
[INFO] os.detected.name: linux
[INFO] os.detected.arch: x86_64
[INFO] os.detected.version: 5.4
[INFO] os.detected.version.major: 5
[INFO] os.detected.version.minor: 4
[INFO] os.detected.release: ubuntu
[INFO] os.detected.release.version: 20.04
[INFO] os.detected.release.like.ubuntu: true
[INFO] os.detected.release.like.debian: true
[INFO] os.detected.classifier: linux-x86_64

```
Here are the dependencies being downloaded related to protoc-gen-grpc-kotlin

```
[INFO] --- protobuf-maven-plugin:0.5.0:compile-custom (grpc-kotlin) @ grpc-hello-world-kotlin ---
Downloading from central: https://repo.maven.apache.org/maven2/io/grpc/protoc-gen-grpc-kotlin/0.1.3/protoc-gen-grpc-kotlin-0.1.1.pom
Downloaded from central: https://repo.maven.apache.org/maven2/io/grpc/protoc-gen-grpc-kotlin/0.1.3/protoc-gen-grpc-kotlin-0.1.1.pom (3.1 kB at 15 kB/s)
Downloading from central: https://repo.maven.apache.org/maven2/io/grpc/protoc-gen-grpc-kotlin/0.1.3/protoc-gen-grpc-kotlin-0.1.1-linux-x86_64.exe
Downloaded from central: https://repo.maven.apache.org/maven2/io/grpc/protoc-gen-grpc-kotlin/0.1.3/protoc-gen-grpc-kotlin-0.1.1-linux-x86_64.exe (21 MB at 1.0 MB/s)

```

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